Chapter 11. Enabling SELinux

After upgrading to Red Hat Gluster Storage 3.1, follow the steps mentioned here for SELinux support. These steps are not mandatory and are required only if SELinux support is required.

This procedure assumes that the selinux-policy-targeted, selinux-policy, libselinux, libselinux-python, libselinux-utils, policycoreutils, policycoreutils-python, setroubleshoot, setroubleshoot-server, setroubleshoot-plugins packages are installed. To verify that the packages are installed, use the following command:

# rpm -q package_name

Important

If the system was initially installed without SELinux, particularly the selinux-policy package, one additional step is necessary to enable SELinux. To make sure SELinux is initialized during system startup, the dracut utility has to be run to put SELinux awareness into the initramfs file system. Failing to do so causes SELinux to not start during system startup.

Before SELinux is enabled, each file on the file system must be labeled with an SELinux context. Before this happens, confined domains may be denied access, preventing your system from booting correctly. To prevent this, configure SELINUX=permissive in /etc/selinux/config:

# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
# enforcing - SELinux security policy is enforced.
# permissive - SELinux prints warnings instead of enforcing.
# disabled - No SELinux policy is loaded.
SELINUX=permissive
# SELINUXTYPE= can take one of these two values:
# targeted - Targeted processes are protected,
# mls - Multi Level Security protection.
SELINUXTYPE=targeted

As the Linux root user, reboot the system. During the next boot, file systems are labeled. The label process labels each file with an SELinux context:

*** Warning -- SELinux targeted policy relabel is required.
*** Relabeling could take a very long time, depending on file
*** system size and speed of hard drives.
****

Each * (asterisk) character on the bottom line represents 1000 files that have been labeled. In the above example, four * characters represent 4000 files have been labeled. The time it takes to label all files depends on the number of files on the system and the speed of hard drives. On modern systems, this process can take as short as 10 minutes.

In permissive mode, the SELinux policy is not enforced, but denial messages are still logged for actions that would have been denied in enforcing mode. Before changing to enforcing mode, as the Linux root user, run the following command to confirm that SELinux did not deny actions during the last boot:

# grep "SELinux is preventing" /var/log/messages

If SELinux did not deny any actions during the last boot, this command returns no output.

If there were no denial messages in /var/log/messages, configure SELINUX=enforcing in /etc/selinux/config:

# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
# enforcing - SELinux security policy is enforced.
# permissive - SELinux prints warnings instead of enforcing.
# disabled - No SELinux policy is loaded.
SELINUX=enforcing
# SELINUXTYPE= can take one of these two values:
# targeted - Targeted processes are protected,
# mls - Multi Level Security protection.
SELINUXTYPE=targeted

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